John P. Cunha, DO, FACOEP

John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

Corticosteroids belonging to the glucocorticoid drug class are used mostly for their strong anti-inflammatory effects and in conditions that are related to the immune system function such as arthritis, colitis (ulcerative colitis, and Crohn's disease), asthma, bronchitis, some skin rashes, and allergic or inflammatory conditions involving the nose and eyes.

What Are the Side Effects of Antihistamines and Corticosteroids?

Antihistamines

First generation antihistamines are used less often to treat allergies because they cause significant sedation. First generation antihistamines also should be used cautiously in older adults as they are more susceptible to their anticholingeric side effects including

Second generation antihistamines are less sedating than their first generation counterparts. Cetirizine can be sedating for some patients at normal recommended doses while sedation seems to only be a concern with loratadine at higher than normally recommended doses. Fexofenadine is the least sedating.

Corticosteroids

Corticosteroids have many side effects that can be mild or serious. These side effects are more apparent when corticosteroids are used at higher doses or for extended periods of time. This section lists only some of these side effects of corticosteroids.

Corticosteroids can:

cause sodium (salt) and fluid to be retained in the body and cause weight gain or swelling of the legs (edema)

The prolonged use of corticosteroids can cause obesity, growth retardation in children, and even lead to convulsions and psychiatric disturbances. Reported psychiatric disturbances include depression, euphoria, insomnia, mood swings, and personality changes. Psychotic behaviors also have been reported.

Corticosteroids, since they suppress the immune system, can lead to an increase in the rate of infections and reduce the effectiveness of vaccines and antibiotics.The long term use of corticosteroids may cause osteoporosis which can result in bone fractures.

Shrinking (atrophy) of the adrenal glands can be caused by the long term use of corticosteroids resulting in the body's inability to produce cortisol, the body's natural corticosteroid, when the systemic corticosteroids are discontinued.

Another condition which can result from the long term use of corticosteroids is adrenal necrosis of the hip joints, a very painful and serious condition that may require surgery. Any symptoms of hip or knee pain in people taking corticosteroids require prompt medical attention.

Corticosteroids should not be stopped suddenly after prolonged use as this can result in adrenal crisis because of the body's inability to secrete enough cortisol to make up for the withdrawal. Nausea, vomiting, and shock are the reported side effects of adrenal crisis.

What Drugs Interact with Antihistamines and Corticosteroids?

Antihistamines

Antihistamines may cause drowsiness. Taking antihistamines with other medicines that also are sedating may cause profound drowsiness. Examples include:

MAOIs (monoamine oxidase inhibitors), a class of medications used to treat mood disorders, may prolong or intensify the anticholinergic side effects of antihistamines.

Generally, first generation antihistamines should not be used within two weeks of using a MAOI.

Corticosteroids

Certain drugs such as troleandomycin (TAO), erythromycin (Ery-Tab, EryPed 200), and clarithromycin (Biaxin) and ketoconazole (Nizoral) can reduce the ability of the liver to metabolize (breakdown) corticosteroids and this may lead to an increase in the levels and side effects of corticosteroids in the body. On the other hand, phenobarbital, ephedrine, phenytoin (Dilantin), and rifampin (Rifadin, Rimactane) may reduce the blood levels of corticosteroids by increasing the breakdown of corticosteroids by the liver. This may necessitate an increase of corticosteroid dose when they are used in combination with these drugs.

Estrogens have been shown to increase the effects of corticosteroids possibly by decreasing their breakdown by the liver.

Corticosteroid effects on warfarin (Coumadin) can vary; therefore when taking warfarin (Coumadin) along with corticosteroids, there may be increased need for monitoring coagulation levels more closely.

Low blood potassium (hypokalemia) and a higher chance of heart failure can result from combining corticosteroids with drugs that reduce potassium in the blood (for example, diuretics, amphotericin B).

Anticholinesterase drugs (for example, physostigmine) may cause severe weakness in some patients with myasthenia gravis when prescribed with corticosteroids. Corticosteroids can increase blood glucose, so close monitoring of blood sugar and higher doses of diabetes medications may be needed.

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Summary

Antihistamines and corticosteroids are used to treat allergy symptoms such as itching, hives, skin rashes, and itchy or watery eyes. Antihistamines also may be used to treat motion sickness, insomnia (difficulty sleeping), and anxiety.